a net. Although no prehistoric net has yet been excavated, fine marks of net on pottery discovered in the Dongsam-dong Shell Midden suggest that nets were widely used not only for fishing but also for hunting in those days. The site has scenes showing whaling activities in great detail. Around 5–17 people are on boats surrounding whales. The bows and sterns are semi-circular and are connected to a harpoon stuck into the body of whales and to floats hanging on a rope. The tools are almost identical to those used by natives for whaling today. Indeterminate figures Engravings of uncertain theme and content have been classified into two types: those of unknown theme which are in good condition and those of unknown shape which have been worn and damaged over time and are therefore hard to decode. Some have signs with certain patterns, but it is hard to classify them on the basis of engravings on the rock alone. Signs are conceptual expressions that are impossible to find in real life but are repeated expressions of a certain pattern. Dating According to the results of an analysis of animal bones discovered in a shell midden in Ulsan and widespread along the southeastern coasts and of research on Ulsan Bay's archaeological environment, the site dates from 6,000 to 1,000 BC. Many relics related to the themes of the rock art were found at Neolithic sites, include deer pattern pottery, net pattern pottery and shell mask discovered in the Dongsam-dong Shell Midden in Busan, a figure with human faces in Osan-ri in Yangyang, a small clay wild pig excavated from the shell midden on Yokjido island of Tongyeong, the clay figure of a woman in Sinam-ri in Ulsan, and a small clay seal excavated from the shell midden in Sejuk-ri, Ulsan. Furthermore, a boat was excavated from the shell midden in Bibong-ri, Changnyeong, and during the Hwangseong-dong site excavation research project conducted by the Korea Archaeology and Art History Research Institute a whale bone stuck with a harpoon was found, which empirically proves whaling. The layers which contain the bones of captured whales date back to 5500 to 4700 BP. Consequently, considering livelihoods in that period, hunting and fishing tools, related relics, and contemporary contents, the rock art seems to have been made between the early and mid-Neolithic era. Before the site was discovered, the first whaling was thought to have taken